The present invention relates to an optical bypass switch for a ring or bus network, and to preferred drive mechanisms therefor, and preferred constructions for bending optical fibers within the switch for coupling light between electro-optic transducers and cores of optical fibers.
Beals et al., U.S. Pat. No. 4,822,125, the disclosure of which is incorporated herein by reference, describes an optical fiber coupler for use in a ring or bus architecture whereby a transmission optical fiber is bent so as to remove a signal therefrom, and also bent so as to inject an optical signal therein, the coupler including attenuating means between the injection and withdrawal locations for attenuating any signal left within the optical fiber so as to improve signal-to-noise ratios between any non-removed portion of the signal in the fiber and that being injected. Though this coupler advantageously allows coupling to the transmission optical fiber in normal use, a need exists for a coupler which is capable of evaluating its state of operation in its bypass state and utilizing this information so as to minimize chances that the coupler will be returned to its normal state when opto-electronic or interconnecting components thereof are not functioning properly.